1. Field of the Invention
The present invention relates to an apparatus for starting a diesel engine actuated when an engine starter motor is rotated, which apparatus comprises an ignition plug installed within a subcombustion chamber, e.g., a swirl chamber of each engine cylinder, instead of an ordinary glow plug so that the engine can start immediately without a preheating process required when the glow plug is used.
2. Description of the Prior Art
Glow plug engine start systems have conventionally been used to start diesel-type internal combustion engines.
A fuel injection valve is installed in a swirl chamber located above a main combustion chamber and interlinked with the main combustion chamber via an injection hole. The glow plug a threaded portion for mounting the plug in the swirl chamber; a heating portion of the plug is exposed in the swirl chamber to aerosol fuel injected from the injection valve. DC voltage is applied to the glow plug from a battery via an ignition key switch. In more detail, a positive pole of the battery is connected to the ignition switch having "START", "ON", "PREHEAT", and "STOP" terminals. The "START" terminal and "PREHEAT" terminal are connected to a pilot lamp and to the glow plugs, one of which is located in each cylinder.
In a conventional engine start system as described above, to start the diesel engine DC current flows from the battery to each glow plug while the ignition switch is set to the "PREHEAT" terminal position. Each glow plug glows with sufficient heat after application of the DC current for several seconds through several tens of seconds. After warm up of the glow plugs, the ignition switch is set to the "START" terminal position to rotate a starter motor to crank the engine while the DC voltage continues to be supplied to the glow plugs. A certain amount of fuel is injected by the fuel injection valve into the swirl chamber which receives and swirls the high-temperature compressed air to start fuel combustion.
However, a problem is that it takes a long time for the engine to start since several seconds through several tens of seconds are required to heat the glow plugs before the engine can be cranked. In addition, a large current of approximately 10 through 15 amperes must be sent through the glow plugs for such a long period of time. Therefore, the capacity of the battery is greatly reduced. This is particularly deleterious when the engine is started under low-temperature ambient conditions.